Research for the development of recent Kurt Cobain documentary "Montage of Heck" introduced director Brett Morgen to Cobain's widespread archives, where he uncovered previously unearthed materials and recordings. Following the film's release, a teenager from Seattle stumbled upon a photo strip of her father and the Nirvana front man playing a basement show together and most recently, an unheard version of Nirvana's "Sappy" has been uploaded to YouTube.